This invention relates to shot blast machines which are commonly used for cleaning articles made from steel and other metals, wherein streams of small metal particles such as grit or shot are directed against the metal articles. Most shot blast machines are large and extremely heavy, and therefore are difficult to move. Thus, it is customary to bring the metal articles to the shot blast machine for cleaning instead of relocating the shot blast machine to a construction site even though the machine may be remotely located with respect to the site where the metal articles are to be used.
When metal articles such as I beams, machinery parts, sheets, plates, grating, pipe and miscellaneous other metal articles are manufactured, the manufacturing site for the metal articles usually is a long distance from the site of construction of the machinery, building, etc. where the metal articles are to be assembled or otherwise used. Thus, the metal articles must be transported from the manufacturing facility to the construction site, and the articles frequently must be stored prior to being assembled or otherwise used. Although the articles may be coated with paint or another rust preventive coating, the protective coatings tend to become damaged during handling of the articles so that the articles are not completely protected as desired.
In some machinery, equipment or building structures it is highly desirable to receive and to assemble the metal articles in virtually perfect condition, without the presence of any surface contaminants. To provide the metal articles in this condition requires the builder or subcontractor to manually treat the articles after delivery thereof at the construction site to remove the contaminants unless a shot blast machine is also located at the construction site. The on-site manual cleaning processes usually are difficult and expensive to undertake because of the massive size and weight of the metal articles, and the prior art cleaning and restoration processes usually must be performed in a controlled environment such as inside a large building.